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Your Guide to Choosing and Storing Dietary Oils




Dietary oils are oils that contain healthy fats for your dog. 


A few of the most commonly used oils in canine diets include flax seed, hemp seed, wheat germ, coconut, and fish. The oils your dog needs depend on the overall composition of his diet (protein types; dietary fat levels, types, and requirements; caloric requirements, etc.) and any health concerns the oils might help improve or prevent.


Fats in the diet are really important, but they can be a bit confusing. Oils are tricky because an imbalance of fats, too much of the wrong type of fat, and feeding rancid fats and oils promote inflammation in the body - the exact thing that dietary oils are meant to counteract.  


Since chronic inflammation is the precursor to most diseases, we want to avoid feeding rancid fats and oils to our dogs.


This article will talk about how to choose quality oils and properly store them so that your dog can get their full health benefits. 


As you read, it's important to remember ... 


Heat, oxygen, and light accelerate the oxidation of oils and fats.

Oil Extraction Process: The Method Matters


The type of extraction method used to separate oil from the plant or fish impacts the oil's purity and potency. We want oils that contain as much of a specific type of fatty acid as possible, and we want to know that the amount of fatty acid stated on the label matches the amount that's actually in the oil. Those are sometimes two very different things, unfortunately. We also want the oil to be as pure and free from harmful contaminants as possible.



Plant Based Oils (flax, hemp, coconut, wheat germ, etc.)


There are a number of ways to extract oil from nuts and seeds. Three of these methods are:

1) Solvent Extraction: Nuts and seeds are ground into a paste and then a solvent, such as hexane, is washed over the paste to extract the oil. The oil and solvent combination is then heated to remove the solvent. Next, the oil is refined, bleached and deodorized (RBD). Solvent extraction is a very efficient method of removing as much oil as possible from plants, but it also involves the use of chemicals and heat, which compromises the quality of the oil. There is some concern that hexane residue may remain on the oil, but it's hard to know for sure since companies are not required to test for its presence.


2) Expeller Pressed: This process applies pressure from a machine to squeeze the oil out of the nut or seed. Chemicals (such as hexane) are not used in this process, but the pressing process creates some heat during the extraction process. It's common for the oil to then be refined, bleached and deodorized.


3) Cold Pressed: The oil is extracted without the use of heat or chemicals in a temperature controlled environment. Cold pressed oils are typically the most expensive oils and are valued for their health benefits.


Fish Oils 


To extract oil from fish, the fish is chopped and then steamed and heated to separate the oil from the solids. The oil is then distilled and cleaned to remove contaminants such as dioxins, PCBs, mercury and other heavy metals. The quality of the oil, the levels of DHA and EPA (Omega-3 fatty acids) in the oil, and the amount of toxins in fish oils vary significantly depending on where the fish was sourced, the species of fish used, whether the fish was wild or farmed, the type of process used to remove toxins, and storage at the manufacturing, retail and consumer levels.


Fish oil intended for use by dogs is often not high enough quality to be sold for humans. I recommend feeding human quality grade supplements, oils, and food to dogs as much as possible, but make sure there is nothing added to the fish oil that would be harmful to your dog. Some human grade fish oils may contain Vitamin D - and your dog may or may not need additional Vitamin D depending on his diet. 


Fish oil should contain an anti-oxidant (vitamin E, for example) which is necessary to slow oxidation. Some human grade fish oils may contain rosemary as the anti-oxidant and this would not be good for dogs with seizure disorders. Always read the label.


Tips For Choosing Dietary Oils


Does your brain feel like it's going to explode when you look at all the health and nutrition products on the market? 


There is an overwhelming amount of fish oil, plant oils, supplements and natural health products available, and it can be equally overwhelming when it comes to choosing which products are best for our dogs. 


These tips are for the ideal product, and you may have to compromise and not tick all of the boxes on this checklist.  When in doubt, always choose glass containers, read the label, and choose human grade products. 


  1. Choose glass bottles. Avoid plastic containers and choose oils in glass containers - dark glass is even better. Plastic is a poor barrier to oxygen. Oxygen and light accelerate the oxidation of fats and oils. Plastic 'breathes' and can allow oxygen molecules to pass through the plastic, into the oil and cause it to degrade. As well, oil can leach chemicals from the plastic which will contaminate the oil. Capsules may be better as long as they are properly sealed. Capsules stored in glass containers are a better choice than capsules in plastic containers.

  2. Choose oils that are non-GMO, organic, hexane free, cold pressed, or expeller pressed. If you want to avoid potential hexane residue buy 100% certified organic oils since hexane is banned for use in organic food production.

  3. Choose human grade oils. Be wary of marketing techniques that convince you to buy dog specific oils. Human grade products are usually much higher quality and more pure than products intended for dogs. 

  4. Check the sourcing. Verify that the manufacturer of your oil is sourcing their fish from waters or countries that have 'clean' production practices and have quality assurance standards and testing. Some oils (fish oils in particular) will have a Natural Product Number (NPN) on the label. An NPN is a number issued by Health Canada and will provide you with an assurance of good manufacturing standards as well as purity and potency of the natural product.

  5. Know the type. We often refer to fatty fish as either 'white fish' or 'orange fish'.  White fish includes herring, sardines, anchovies, and mackerel. Salmon is called an orange fish. Some dogs may have an intolerance to either 'white' fish or 'orange' fish, so it's good to know what kind of fish your dog's fish oil is made from.

  6. Read labels. Determine if there are additional ingredients added to the oil  - watch out for added vitamins or supplements that your dog may not need. Some fish oils contain added Vitamin D, which your dog may or may not need, depending on his diet.

  7. Third Party Testing. Look for independent third party testing of oils to verify purity and potency. Look for a GMP (Good Manufacturing Practices) or similar icon. Fish oil may have an MSC (Marine Stewardship Council) certification icon.

  8. Buy small amounts. Buy only the amount of oil you anticipate using within 4 months.

Tips For Storing Oils


Proper storage of dietary oils is the second step in avoiding feeding rancid fats to your dog.


Remember that heat, light, and oxygen accelerate oxidation of fats.

  1. Storage. Store oils in a cool, dark, dry location. Some oils should be kept in the refrigerator. Check the label for storage instructions. As a rule of thumb, fish oil, flax seed oil, hemp seed oil, and wheatgerm oil should be refrigerated.

  2. Caps on. Keep the lids on all bottles of oils.

  3. Use oils within about 3 - 4  months. After that point, the oil will be oxidized and is no longer healthy for your dog.

  4. Keep track of dates. Write the date when you opened the oil on either the cap or the label so that you know when it's time to stop using the dietary oil.

Can I freeze fish oil?


As with so many areas of dog nutrition, there is some debate over whether freezing fish oil will slow down or contribute to oxidation. I follow Steve Brown's guidance in this area. In his book, Unlocking the Canine Ancestral Diet, Brown summarizes that what can oxidize will oxidize, and that freezing damages the double bonds in Omega-3 fats which promotes oxidation. 


My best advice is to not freeze fish oil, and to avoid commercial raw diets that contain added frozen fish oil. Dietary oils should be stored in their glass containers and then added just before serving.


Extra Reading: Why fish is important in the canine diet 


Omega-3 fatty acids are crucial for your dog. The 3 main types of Omega-3 fatty acids are: ALA, EPA, and DHA. ALA comes from some plant sources, while EPA and DHA come from marine sources (and brains, just in case you want to feed brains to your dog). EPA and DHA are the two types of Omega-3 fats that your dog's body can use. Dogs are very inefficient at converting ALA to EPA and DHA.


My first choice for meeting your dog's EPA and DHA  requirements is by feeding small fatty fish - salmon, mackerel, sardines, herring, anchovies, etc. If you cannot give your dog fish, or cannot supply enough fish to meet his EPA and DHA requirements, you may need to rely on fish oil.


Again, fatty fish and fish oil contain DHA and EPA. These are commonly referred to as marine sourced Omega-3s since fish are very rich sources of EPA and DHA.  There are a multitude of studies that prove the important role that EPA and DHA have on the health of dogs - and people. Research shows there are significant improvements in skin and coats, joint, brain and cognition, mood, and cardiovascular health when EPA and DHA are included at optimum levels in the diet. Omega-3 fatty acids reduce inflammation and regulate the immune system.


Coconut oil does not contain EPA or DHA. and it is not a substitute for fish or fish oil. Some plant based oils (flax, for example) contain the Omega-3 fat, ALA. If your dog has a fish or seafood intolerance, then you will need to use plant based Omega-3s, but bear in mind that it is not the ideal type of Omega-3 for dogs.


For More Reading ... 




* These suggestions are for healthy dogs. This article is for information purposes only. Every dog is different and has a different tolerance level for new foods. Please always do your own research when making health decisions for your dog. You are your dog's best health care advocate.

© 2019 by Green Dog

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